Driver for Texas Instruments TI ADS1115 analog-to-digital converter, written in Python

Once initialized, the input voltage measurement will be queued in data, in the background every 500ms. Then, get_measurement() method can be called to pull a datapoint from the queue. Each datapoint contains a timestamp, which can be used to identify the time when the specific measurement was taken. Please see example and output structure below.

Conditions:

• Vcc = 5V
• 4 analog inputs, IN0, IN1, IN2, and IN3
• Reference of measurement: GND
• Maximum voltage of analog input <= Vcc

import sys
import json
from time import sleep
from ads1115 import ADS1115, PGA, I2CBus, I2CAddress


adc = ADS1115(bus=1,
              pga=PGA.FSR_6_144,
              address=I2CAddress.X48)

while True:
    try:
        print(json.dumps(adc.get_measurement(), indent=2))
        sleep(2)

    except KeyboardInterrupt:
        sys.exit(1)

{
  "input_voltage": {
    "in0_in1": 4.68261,
    "in0_in3": 4.1965,
    "in1_in3": -0.5054,
    "in2_in3": 0.61341,
    "in0_gnd": 5.03286,
    "in1_gnd": 0.33044,
    "in2_gnd": 1.44925,
    "in3_gnd": 0.81636
  },
  "timestamp": 1627898911
}

The "input_voltage" key consists of 8 key-value pairs. Key name is self-explanatory, i.e. measurement taken between 2 points. The value is the voltage of measurement in Volt. As the example of measurement is made between analog input INx and GND, then key-value pairs we are interested in are

• "in0_gnd": 5.03286
• "in1_gnd": 0.33044
• "in2_gnd": 1.44925
• "in3_gnd": 0.81636

These voltage were taken at timestamp, measured in seconds since the Unix epoch.